here's my quandry.... let's say i hava an a2k app. let's say there's a form and the bound controls that interest us are MR_Number (medical record number), IRB_Number (the number of a clinical experiment on which a patient is enrolled), RegisteredDate (the date on which the patient was registered on the IRB_Number) and FollowUpDate (the next scheduled follow-up visit date), and lastly a field called ECOG (don't worry about what it means---it's binary e.g. Yes/No). i don't know if this aspect of the situation is all that important, but the same MR_Number can appear on more than one IRB_Number (but not at the same time--this would happen if a patient dropped out of an experiment for some reason and then managed to be re-enrolled in a different one later on). let's say that the default value of ECOG's is "Yes" for each patient. when it's 'Yes', then the control source for FollowUpDate would be a certain query and that when it's "No" that the control source for FollowUpDate would be a different query. in each case a date value would be entered into FollowUpDate but it would be computed using slightly different follow-up schedules. is this doable?